p {
  margin: 0;
  padding: 10px;
}

.my-head {
  height: 44px;
  line-height: 44px;
  padding: 0 20px;
  background: #ddd;
  text-align: center;
}

.my-head a.left {
  float: left;
}

.my-head a.right {
  float: right;
}

#home_wrapper,
#about_wrapper,
#list_wrapper,
#four_wrapper {
  position: absolute;
  top: 44px;
  left: 0;
  bottom: 0;
  width: 100%;
  padding: 0 20px;
  box-sizing: border-box;
}